Synthetic riboswitches that induce gene expression in diverse bacterial species

We developed a series of ligand-inducible riboswitches that control gene expression in diverse species of Gram-negative and Gram-positive bacteria, including human pathogens that have few or no previously reported inducible expression systems. We anticipate that these riboswitches will be useful tools for genetic studies in a wide range of bacteria.     

Spatial heterogeneity in the perception of face and form attributes

The identity of an object is a fixed property, independent of where it appears, and an effective visual system should capture this invariance [1-3]. However, we now report that the perceived gender of a face is strongly biased toward male or female at different locations in the visual field. The spatial pattern of these biases was distinctive and stable for each individual. Identical neutral faces looked different when they were presented simultaneously at locations maximally biased to opposite genders. A similar effect was observed for perceived age of faces. We measured the magnitude of this perceptual heterogeneity for four other visual judgments: perceived aspect ratio, orientation discrimination, spatial-frequency discrimination, and color discrimination. The effect was sizeable for the aspect ratio task but substantially smaller for the other three tasks. We also evaluated perceptual heterogeneity for facial gender and orientation tasks at different spatial scales. Strong heterogeneity was observed even for the orientation task when tested at small scales. We suggest that perceptual heterogeneity is a general property of visual perception and results from undersampling of the visual signal at spatial scales that are small relative to the size of the receptive fields associated with each visual attribute.     

High prevalence of the metabolic syndrome in Iranian adolescents

Objective : No evidence exists regarding the prevalence of the metabolic syndrome in adolescents in Middle Eastern countries. We aimed to evaluate the prevalence of the metabolic syndrome in a representative sample of Iranian adolescents. Research Methods and Procedures : Anthropometry, biochemical measurements, and blood pressure were assessed in a population‐based cross‐sectional study of 3036 Iranian adolescents (1413 boys and 1623 girls) 10 to 19 years of age. Metabolic syndrome was defined according to modified Adult Treatment Panel III definition. Overweight (≥95th percentile) and at risk for overweight (≥85th to <95th percentile) was defined based on the standardized percentile curves of BMI suggested for Iranian adolescents. Results : The prevalence of the metabolic syndrome was 10.1% (95% confidence interval: 9.0 to 11.1) among Iranian adolescents (boys: 10.3%, 8.6 to 11.8; girls: 9.9%, 8.4 to 11.3). Overall, low serum high‐density lipoprotein‐cholesterol and high serum triglycerides were the most common components of the metabolic syndrome (42.8% and 37.5%, respectively). Overweight subjects had the highest proportion of metabolic syndrome compared with those at risk for overweight and those with normal weight (boys: 41.1% vs. 11.4% and 3.0%, respectively, p < 0.01; girls: 43% vs. 15.2% and 5.0%, respectively, p < 0.01). Discussion : This study provides evidence showing a high prevalence of the metabolic syndrome in Iranian adolescents, particularly among overweight adolescents.     

Coordinate regulation of small temporal RNAs at the onset of Drosophila metamorphosis

The lin-4 and let-7 small temporal RNAs play a central role in controlling the timing of Caenorhabditis elegans cell fate decisions. let-7 has been conserved through evolution, and its expression correlates with adult development in bilateral animals, including Drosophila [Nature 408 (2000), 86]. The best match for lin-4 in Drosophila, miR-125, is also expressed during pupal and adult stages of Drosophila development [Curr. Biol. 12 (2002), 735]. Here, we ask whether the steroid hormone ecdysone induces let-7 or miR-125 expression at the onset of metamorphosis, attempting to link a known temporal regulator in Drosophila with the heterochronic pathway defined in C. elegans. We find that let-7 and miR-125 are coordinately expressed in late larvae and prepupae, in synchrony with the high titer ecdysone pulses that initiate metamorphosis. Unexpectedly, however, their expression is neither dependent on the EcR ecdysone receptor nor inducible by ecdysone in cultured larval organs. Although let-7 and miR-125 can be induced by ecdysone in Kc tissue culture cells, their expression is significantly delayed relative to that seen in the animal. let-7 and miR-125 are encoded adjacent to one another in the genome, and their induction correlates with the transient appearance of an approximately 500-nt RNA transcribed from this region, providing a mechanism to explain their precise coordinate regulation. We conclude that a common precursor RNA containing both let-7 and miR-125 is induced independently of ecdysone in Drosophila, raising the possibility of a temporal signal that is distinct from the well-characterized ecdysone-EcR pathway.     

Transmission of the Subthalamic Nucleus Oscillatory Activity to the Cortex: A Computational Approach

Parkinsonian tremor is most likely due to oscillatory neuronal activities of central oscillators such as the subthalamic nucleus (STN)-external segment of the globus pallidus (GPe) pacemaker within the basal ganglia (BG). Activity from the central oscillator is proposed to be transmitted via transcortical pathways to the periphery. A computational model of the BG is proposed for simulating the transmission of the STN oscillatory activity to the cortex, based closely on known anatomy and physiology of the BG. According to the results of the simulation, for transmission of the STN oscillatory activity to the cortex, the STN oscillatory activity has to be transmitted simultaneously to the thalamus via STN-internal segment of the globus pallidus (GPi)-thalamus and STN-GPe-GPi-thalamus pathways. This transmission is controlled by the various factors such as the phase between the STN and GPe oscillatory activities, the STN oscillatory activity frequency, the low-threshold calcium spike bursts of the thalamus and the GPi spontaneous activity.     

Role of Src protein tyrosine kinases in late preconditioning against myocardial infarction

Although Src protein tyrosine kinases (PTKs) have been shown to be essential in late preconditioning (PC) against myocardial stunning, their role in triggering versus mediating late PC against myocardial infarction remains unclear. Four groups of conscious rabbits were subjected to a 30-min coronary occlusion on day 2, with or without PC ischemia on day 1. Administration of the Src PTK inhibitor lavendustin A (LD-A; 1 mg/kg iv) before the PC ischemia on day 1 (group III, n = 7) failed to block the delayed protective effect against myocardial infarction 24 h later. Late PC against infarction, however, was completely abrogated when LD-A was given 24 h after the PC ischemia, prior to the 30-min occlusion on day 2 (group IV, n = 8). We conclude that, in conscious rabbits, Src PTK activity is necessary for the mediation of late PC protection against myocardial infarction on day 2, but not for the initiation of this phenomenon on day 1. Taken together with previous studies in the setting of stunning, these findings reveal heretofore unrecognized differences in the roles of Src PTKs in late PC against stunning versus late PC against infarction.     

Binding of Protein Kinase C Isoforms to Actin in Aplysia

Abstract: Recently, two of the 10 vertebrate protein kinase C (PKC) isoforms, PKCβII and PKCε, have been shown to bind specifically to actin filaments, suggesting that these kinases may regulate cytoskeletal dynamics. Here, we present evidence that two PKCs from the marine mollusk Aplysia californica , PKC Apl I, a Ca²⁺-activated PKC, and PKC Apl II, a Ca²⁺-independent PKC most similar to PKCε and η, also bind F-actin. First, they both cosedimented with purified actin filaments in a phorbol ester-dependent manner. Second, they both translocated to the Triton-insoluble fraction of the nervous system after phorbol ester treatment. PKC Apl II could also partially translocate to actin filaments and associate with the Triton-insoluble fraction in the absence of phorbol esters. Translocation to purified actin filaments was increased in the presence of a PKC inhibitor, suggesting that PKC phosphorylation reduces PKC bound to actin. Although both kinases bound F-actin, actin was not sufficient to activate the kinases. In support of a physiological role for actin-PKC interactions, immunochemical localization of PKC Apl II in neuronal growth cones revealed a striking colocalization with F-actin. Our results are consistent with a role for actin-PKC interactions in regulating cytoskeletal dynamics in Aplysia .     

Upregulation of MAPKAPK5-AS1, PXN-AS1 and URB1-AS1 lncRNAs in non-functioning pituitary adenoma

Long non-coding RNAs (lncRNAs) have been shown to be dysregulated in a variety of malignant and non-malignant lesions including non-functioning pituitary adenomas (NFPAs). In the current experimental study, we have selected six lncRNAs, namely MAPKAPK5-AS1, NUTM2B-AS1, ST7-AS1, LIFR-AS1, PXN-AS1 and URB1-AS1 to assess their expression in a cohort of Iranian patients with NFPA. MAPKAPK5-AS1, PXN-AS1 and URB1-AS1 were shown to be over-expressed in NFPA tissues compared with control samples (Expression ratios (95% CI) = 10 (3.94–25.36), 11.22 (4.3–28.8) and 9.33 (4.12–21.12); p values < 0.0001, respectively). The depicted ROC curves showed the AUC values of 0.73, 0.80 and 0.73 for MAPKAPK5-AS1, PXN-AS1 and URB1-AS1, respectively. Relative expression level of PXN-AS1 was associated with tumour subtype (p value = 0.49). Besides, relative expression levels of MAPKAPK5-AS1 and LIFR-AS1 were associated with gender of patients (p values = 0.043 and 0.01, respectively). Cumulatively, the current study indicates the possible role of MAPKAPK5-AS1, PXN-AS1 and URB1-AS1 lncRNAs in the pathogenesis of NFPAs.     

Investigation of Microstructure and Corrosion of TiNbTaZrMo High-Entropy Alloy in the Simulated Body Fluid

Microstructures and corrosion of TiNbTaZrMo(Ti₂₀Nb₂₀Ta₂₀Zr₂₀Mo₂₀)High-Entropy Alloy(HEA)were investigated in the Simu-lated Body Fluid(SBF).Microstructure of this alloy was investigated by X-Ray Difiraction(XRD)and Scanning Electron Microscopy(SEM)techniques.Our observations confirmed the presence of two bcc phases as the major matrix as well as another minor phase in themicrostructure of the alloy.Concentration of some elements,such as tantalum,niobium,and molybdenum in the dendritic branches and thepresence of zirconium and titanium in the inter-dendritic branches were clearly evidenced by Energy Dispersive X-ray(EDX)analysis.Given importance of corrosion of implant alloys in the human's body,elctrochemical impedance and cyclic polarization tests werepcerformed on the alloy in SBF.Through the corrosion tests,corrosion potential,current,and resistance were obtained as E_corr=-0.42 V,i_corr=0.34μA·cm^-2,and R_p=27.44 k ohm·cm²,respectively.The results revealed that the rate of corrosion in TiNbTaZrMo HEA is about 26 times better than that of Ti₆Al₄V alloy.Also,both alloys had no pitting corrosion in the SBF solution.